U.S. patent number 4,421,179 [Application Number 06/227,587] was granted by the patent office on 1983-12-20 for top drive well drilling apparatus.
This patent grant is currently assigned to Varco International, Inc.. Invention is credited to George I. Boyadjieff.
United States Patent |
4,421,179 |
Boyadjieff |
December 20, 1983 |
Top drive well drilling apparatus
Abstract
Well drilling apparatus including a powered drilling unit
connectable to the upper end of a drill string and adapted to
rotate it to drill a well, and a vertically extending guide track
structure which guides the drilling unit for movement along the
axis of the well, with a portion of the guide track structure being
mounted for swinging movement between a drilling position in which
the drilling unit is aligned with the axis of the well and a
slightly inclined position in which the track structure guides the
drilling unit for movement along an inclined axis in alignment with
a mousehole, and with the drilling unit also preferably being
mounted for movement to a laterally retracted position at a side of
the well in which it leaves an area along the axis of the well
unobstructed for use of conventional hoisting equipment in making a
`round trip` of the drill string out of and then back into the
well.
Inventors: |
Boyadjieff; George I. (Anaheim,
CA) |
Assignee: |
Varco International, Inc.
(Orange, CA)
|
Family
ID: |
22853690 |
Appl.
No.: |
06/227,587 |
Filed: |
January 23, 1981 |
Current U.S.
Class: |
173/44;
175/85 |
Current CPC
Class: |
E21B
19/02 (20130101); E21B 15/00 (20130101); E21B
19/14 (20130101) |
Current International
Class: |
E21B
19/02 (20060101); E21B 15/00 (20060101); E21B
3/00 (20060101); E21B 19/00 (20060101); E21B
19/14 (20060101); E21B 3/02 (20060101); E21B
015/00 (); E21B 019/00 () |
Field of
Search: |
;173/42,43,44,39
;175/52,85 ;414/22 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Smith; James G.
Assistant Examiner: Adolphson; K. Bradford
Attorney, Agent or Firm: Green; William P.
Claims
I claim:
1. Well drilling apparatus comprising:
a mast or derrick;
a drilling unit including an element adapted to be connected to the
end of a drill string for rotation therewith about the axis of the
string, and a motor operable to drive said element and the
connected string rotatively about said axis;
a pair of elongated first guide rails;
a pair of shorter second guide rails forming lower extensions of
said first rails;
a carriage by which said drilling unit is carried and engaging said
rails for movement therealong between an upper position of guided
engagement with said first rails and a lower position of guided
engagement with said second rails;
pivotal connection means mounting said first rails near their upper
ends for swinging movement of said first rails and said second
rails and said carriage and carried drilling unit relative to said
mast or derrick between drilling positions in which said carriage
and drilling unit are guided by said first and second rails for
movement along said axis of the drill string and inclined positions
in which the first and second rails extend at an angle to said axis
and guide the carriage and drilling unit for movement along an
inclined path at an angle to the axis for access to a mousehole;
and
a connection mounting at least one of said second rails to a
corresponding one of said first rails for movement therewith
between said drilling and inclined positions, and for swinging
movement relative thereto with said carriage and drilling unit to
move the drilling unit from an active position of alignment with
said axis to a retracted position at a side of the axis.
2. Well drilling apparatus as recited in claim 1, including powered
means for swinging said first and second rails together relative to
said mast or derrick between said drilling positions and said
inclined positions thereof.
3. Well drilling apparatus as recited in claim 2, including latch
means for releasably retaining said first and second rails in said
drilling positions.
4. Well drilling apparatus as recited in claim 1, including a pair
of third rails carried by said derrick above said first and second
rails and in alignment therewith when the first and second rails
are in their drilling positions, and which remain stationary while
the first and second rails swing to said inclined positions
thereof.
5. Well drilling apparatus as recited in claim 4, including a
second carriage engageable with said first and third rails at a
location spaced above said first carriage and guided by the first
and third rails for movement therealong, and a traveling block
connected to said second carriage and located thereby and operable
to suspend said drilling unit when it is in said active position
and to suspend a drill string independently of the drilling unit
when the latter is in its retracted position.
6. Well drilling apparatus as recited in claim 5, including means
connecting said drilling unit to said first mentioned carriage for
slight pivotal movement relative thereto about an essentially
horizontal axis and to a slightly inclined position when said first
carriage is in engagement with said third rails.
7. Apparatus for drilling a well along a predetermined axis by
rotation of a drill string about said axis, comprising:
an upwardly projecting drill rig mast or derrick;
a drilling unit including an element adapted to be connected to the
end of said drill string for rotation therewith about the axis of
the string, and a motor operable to drive said element and the
connected string rotatively about said axis;
an elongated first guide structure which in a predetermined
drilling position extends essentially parallel to said axis and
guides the drilling unit for movement along said axis;
means mounting said elongated first guide structure for swinging
movement relative to said mast or derrick between said drilling
position of extension essentially parallel to said axis and an
inclined position in which the guide structure extends at an angle
to said axis and guides the drilling unit for movement along an
inclined path at an angle to the axis; and
an upper elongated guide structure above said first guide structure
and which is essentially aligned with and forms a continuation of
said first guide structure in said drilling position of the first
guide structure to guide the drilling unit for movement along said
axis upwardly beyond the first guide structure;
said upper guide structure being constructed to remain in a
position of extension essentially parallel to said axis when said
first guide structure swings relative to said mast or derrick to
said inclined position.
8. Apparatus as recited in claim 7, including a carriage which is
movable along said guide structures and carries said drilling unit,
and means connecting said drilling unit to said carriage for slight
pivotal movement relative thereto about an essentially horizontal
axis to enable positioning of the drilling unit at a slight
inclination when the carriage is in engagement with said upper
guide structure.
9. Apparatus as recited in claim 7, including a carriage which is
movable along said guide structures and carries said drilling unit,
means connecting said drilling unit to said carriage for slight
pivotal movement relative thereto about an essentially horizontal
axis to enable positioning of the drilling unit at a slight
inclination when the carriage is in engagement with said upper
guide structure, and means yieldingly resisting said slight pivotal
movement of said carriage to said inclined position when said
carriage is in engagement with said upper guide structure.
10. Apparatus as recited in claim 7, including a carriage which is
movable along said guide structures and carries said drilling unit,
and means connecting said drilling unit to said carriage for slight
pivotal movement relative thereto.
11. Apparatus for drilling a well along a predetermined axis by
rotation of a drill string about said axis comprising:
an upwardly projecting drill rig mast or derrick;
a drilling unit including an element adapted to be connected to the
end of said drill string for rotation therewith about the axis of
the string, and a motor operable to drive said element and the
connected string rotatively about said axis;
an elongated guide structure which in a predetermined drilling
position extends essentially parallel to said axis and guides the
drilling unit for movement along said axis; and
means mounting said elongated guide structure for swinging movement
relative to said mast or derrick between said drilling position of
extension essentially parallel to said axis and an inclined
position in which the guide structure extends at an angle to said
axis and guides the drilling unit for movement along an inclined
path at an angle to the axis;
said elongated guide structure having aligned upper and lower
sections which swing together relative to said mast or derrick
between said drilling and inclined positions;
said drilling unit being movable downwardly along the guide
structure from a position in which it is guided by said upper
section of the guide structure to a position in which it is guided
by said lower section;
there being means mounting at least a portion of said lower section
of the guide structure for movement with said drilling unit
relative to said upper section of the guide structure between an
active position in which the drilling unit is aligned with said
axis and a retracted position at a side of said axis.
12. Apparatus for drilling a well along a predetermined axis by
rotation of a drill string about said axis, comprising:
an upwardly projecting drill rig mast or derrick;
a drilling unit including an element adapted to be connected to the
end of said drill string for rotation therewith about the axis of
the string, and a motor operable to drive said element and the
connected string rotatively about said axis;
an elongated guide structure which in a predetermined drilling
position extends essentially parallel to said axis and guides the
drilling unit for movement along said axis;
means mounting said elongated guide structure for swinging movement
relative to said mast or derrick between said drilling position of
extension essentially parallel to said axis and an inclined
position in which the guide structure extends at an angle to said
axis and guides the drilling unit for movement along an inclined
path at an angle to the axis;
a carriage by which said drilling unit is carried and which engages
said guide structure for movement therealong with the drilling
unit;
said guide structure having upper and lower sections;
said mounting means including pivotal connection means at an upper
end of said upper section of the guide structure mounting said
upper section for swinging movement of its lower end relative to
said mast or derrick generally horizontally between said drilling
and inclined positions;
there being means connecting said lower section of the guide
structure to said upper section for swinging movement therewith and
for movement of at least a portion of the lower section relative to
the upper section between an active position of alignment with the
upper section and a retracted position offset laterally with
respect to the upper section;
said carriage and drilling unit being movable along the guide
structure from an upper position of guided engagement with said
upper section to a lower position in which the carriage engages
said lower section of the guide structure and moves relative to the
upper section with the drilling unit between said active and
retracted positions.
Description
BACKGROUND OF THE INVENTION
This invention relates to improved well drilling apparatus adapted
to drive a drill string without the use of a rotary table, kelly,
and kelly bushing.
In order to avoid the necessity for a rotary table and its related
equipment in a well drilling rig, there have been devised in the
past arrangements employing a drilling unit having a pipe section
connectable to the upper end of a drill string and a motor for
driving that pipe section rotatively and thereby driving the string
to perform a drilling operation. In some instances, the drilling
unit has been mounted on a carriage which is guided by vertical
tracks for movement along those tracks axially of the well to
advance with the string as the drilling operation progresses. In
one prior arrangement of this type, the drilling unit is connected
pivotally to the carriage to swing relative to the carriage and
tracks to an inclined position of alignment with a mousehole in
order to pick up a pipe section from or place it into the
mousehole. Abandoned Application Ser. No. 167,758 filed July 14,
1980 by Boyadjieff et al. on "Well Drilling Apparatus" shows a
system in which the drilling unit is bodily shiftable horizontally
between a drilling position of alignment with the well axis and a
position of vertical alignment with a mousehole, and also is
mounted for horizontal swinging movement relative to the main
portion of the track structure to a laterally retracted position at
a side of the well.
SUMMARY OF THE INVENTION
The present invention provides an improved drilling system of the
above discussed general type, in which the drilling unit is movable
from a drilling position of alignment with the well axis to a
mousehole position, and preferably also to a retracted position at
a side of the well permitting a `trip` of the drill string into or
out of the well by other equipment, and which is so constructed as
to afford a very rugged and effective support for the drilling unit
in all of these various positions. Further, the apparatus acts to
positively guide the drilling unit for movement along predetermined
controlled paths in both the drilling position of the unit and its
mousehole position, and to power actuate the unit between those two
positions. In addition, all of these results are achieved with
apparatus which is extremely simple structurally and therefore
inexpensive to manufacture and maintain and capable of functioning
over long periods of time without operational difficulties.
A major feature of the present invention resides in the unique way
that a drilling unit embodying the invention is mounted for
movement between its drilling and mousehole positions. This
movement is accomplished by mounting at least part of the elongated
guide or track structure for slight pivotal movement between a
drilling position in which the guide structure mounts the drilling
unit for movement along the vertical axis of the drill string and
an inclined position in which the guide structure is disposed at a
slight angle to the axis of the drill string and is inclined in
alignment with a mousehole. The powered drilling unit, including a
pipe section connectable to the drill string and a motor for
driving that pipe section, swings with the guide or track structure
between its discussed drilling and mousehole positions, and is
guided by the guide structure for movement therealong in both of
those positions. Preferably, the guide structure is movable by a
power unit between its drilling and mousehole positions, and has
latch means for releasably retaining the entire structure in the
drilling position.
In addition to its swinging movement with the track structure, the
drilling unit is preferably also mounted for movement laterally or
generally horizontally relative to the major portion of the track
structure between the drilling position and a laterally offset
retracted position away from the axis of the drill string, to
permit a trip of the string into or out of the hole by the usual
traveling block and related equipment. The lower portion of the
guide track structure may be constructed to allow for such lateral
shifting movement of the drilling unit to a retracted position when
the drilling unit is in a lowermost position on the guide
structure. Desirably, one of two guide rails has a lower portion
which is mounted for pivotal movement in a manner swinging the
guide unit when connected to that lower rail portion to its
retracted position.
Additional features of the invention relate to a preferred
structure for the drilling unit, in which the tubular driven shaft
of the unit, which is connected to and drives the drill string, is
mounted rotatably at a side of the case of the drilling unit motor,
by bearings which are secured to the motor case at spaced locations
near the opposite ends of the motor armature.
BRIEF DESCRIPTION OF THE DRAWINGS
The above and other features and objects of the invention will be
better understood from the following detailed description of the
typical embodiments illustrated in the accompanying drawings, in
which:
FIG. 1 is a front elevational view of well drilling apparatus
embodying the present invention;
FIG. 2 is a side elevational view taken on line 2--2 of FIG. 1 but
showing the drilling unit swung to its mousehole position;
FIG. 3 is a fragmentary front elevational view showing the drilling
unit swung to its retracted position permitting a trip of the well
pipe into or out of the well;
FIG. 4 is an enlarged fragmentary plan view taken on line 4--4 of
FIG. 1;
FIG. 5 is an enlarged fragmentary vertical section taken on line
5--5 of FIG. 1;
FIG. 6 is a fragmentary horizontal section taken on line 6--6 of
FIG. 5;
FIG. 7 is a reduced fragmentary front elevational view of the
drilling unit taken on line 7--7 of FIG. 5;
FIG. 8 is a fragmentary vertical section taken on line 8--8 of FIG.
7;
FIG. 9 is an enlarged fragmentary representation of a portion of
FIG. 2;
FIG. 10 is an enlarged fragmentary horizontal section taken on line
10--10 of FIG. 2; and
FIG. 11 is a view corresponding to a portion of FIG. 5 but showing
a variational quick disconnect type of shaft assembly for the
drilling unit.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The drilling rig 10 illustrated in FIG. 1 includes a derrick 11
projecting upwardly above a location at which a well bore 12 is
being drilled by a rotary drill string 13 formed in conventional
manner of a series of drill pipe stands connected together in
end-to-end fashion at threaded connections 14. The string 13 is
turned about the vertical axis 15 of the well by a drilling unit 16
formed in accordance with the invention and connected to the upper
end of the string. The drill string and unit 16 are supported and
adapted to be moved upwardly and downwardly by the usual hoisting
mechanism 17 including a crown block 18, traveling block 19, tackle
20 supporting block 19 from block 18, and power driven draw works
for reeling the line 20 in or out to raise or lower the traveling
block. The traveling block supports a hook 21 from which the
drilling unit is suspended, and which has a gate 121 adapted to be
opened for connecting and disconnecting the drilling unit. The
drilling unit 16 and hook 19 are guided during their upward and
downward movement by two sectionally formed parallel elongated
guide rails 22 and 23, engaging and guiding a carriage 24 forming a
portion of the drilling unit and a carriage 25 to which the
traveling block is connected.
The two sectionally formed guide rails 22 and 23 are preferably of
H-shaped horizontal sectional configuration as illustrated in FIGS.
4 and 10. This H-shaped cross section continues from the upper
extremity of each rail to its lower extremity. The rails 22 and 23
have upper sections 22a and 23a, which extend from the upper end of
derrick 11 to the locations 26 of FIG. 1, and are attached rigidly
to the derrick for retention stationarily in positions of extension
directly vertically and parallel to one another and to well axis
15. Beneath the locations 26, the two guide rails 22 and 23 have
second portions or sections 22b and 23b, extending parallel to one
another and continuing downwardly from the locations 26 to
locations 27 of FIG. 3. These sections 22b and 23b are mounted by
two pivotal connections 28 for swinging movement relative to upper
sections 22a and 23a and about a horizontal axis 29' between the
full line and broken line positions of FIG. 2. In the broken line
positions of FIG. 2, rail sections 22b and 23b are disposed
directly vertically and directly parallel to well axis 15 and are
in vertical alignment with upper sections 22a and 23a respectively
to form vertical continuations thereof. In the full line position
of FIG. 2, sections 22b and 23b remain parallel to one another but
are inclined at a slight angle a with respect to the vertical and
with respect to the longitudinal axes of upper rail sections 22a
and 23a, to bring the axis 29 of the drilling unit in alignment
with an inclined mousehole 30 located a short distance forwardly of
the main axis 15 of the well.
Beneath portions 22b and 23b of sectionally formed rails 22 and 23,
those rails have third lowermost sections 22c and 23c, which are
carried by sections 22b and 23b respectively for swinging movement
therewith between the vertical and inclined positions of FIG. 2,
and which also are mounted by connections 31 and 32 (FIGS. 2, 3 and
9) for horizontal swinging movement relative to sections 22b and
23b respectively about two axes 33 and 34 which are parallel to one
another and to the longitudinal axes 35 and 36 of sections 22b and
23b. This pivoted movement of lower rail sections 22c and 23c
mounts those sections for movement between the full line active
positions of FIG. 4 in which they are in longitudinal alignment
with and form lower continuations of rail sections 22b and 23b
respectively, and the broken line retracted positions of FIG.
4.
The two pivotal connections 31 and 32 preferably include two
parallel mounting pipes or tubes 37 and 38 centered about axes 33
and 34 and connected rigidly to sections 22b and 23b at the back
thereof, as by welding or by attachment to mounting rings or clamps
39 secured rigidly to sections 22b and 23b and extending about and
attached rigidly to the upper ends of pipes 37 and 38. Near their
upper ends, each of the lower sections 22c and 23c may carry a
bearing sleeve 40 which extends about the associated tube 37 and 38
and fits closely thereon to locate the upper portion of the section
22c or 23c for the desired pivotal motion about axis 33 or 34. At
their lower ends, rail sections 22c and 23c may carry bottom plates
41 projecting inwardly beneath pipes 37 and 38 and having bearings
42 disposed about lower pivot pins 43 projecting downwardly from
the two pipes in a relation supporting the weight of the lower
sections 22c and 23c from pipes 37 and 38 while permitting pivotal
movement of sections 22c and 23c about axes 33 and 34. Plate 41
extends horizontally across the bottom of each of the lower rail
sections 22c and 23c, and is welded thereto, and functions as a
stop preventing movement of carriage 24 downwardly off of the
rails.
The two rail sections 22b and 22c are adapted to be power actuated
between the vertical and inclined positions of FIG. 2 by a piston
and cylinder mechanism 45 (FIGS. 2 and 9), whose cylinder is
connected at 46 to a horizontally extending stationary portion 47
of the derrick, and whose piston rod 48 acts against the tube 37 of
pivotal connection 31. In the vertical position of rail section
22c, its associated mounting tube 37 may bear against an arcuately
curved stop member 49 acting to effectively locate the swinging
rail sections in their vertical condition. A latch element 50
pivoted at 51 to a bracket 52 projecting rearwardly from and welded
or otherwise secured to tube 37 is engageable with a coacting latch
part 53 fixed stationarily to the derrick and to parts 47 and 49,
to positively hold tube 37 and the connected rail parts in their
vertical drilling positions. The piston rod 48 of mechanism 45 may
be pivotally connected at 44 to a downwardly projecting arm 54 of
latch element 50, in a relation pivoting the latch element in a
counter clockwise direction and from its holding position to a
released position in response to rightward actuation of the piston
rod 48. This pivotal movement of latch element 50 is limited by
engagement of piston rod 48 with tube 37, so that upon rightward
actuation of the piston rod it acts first to release the latch
element and then push rail sections 22b and 22c rightwardly to the
full line inclined position of FIG. 2. Upon powered returning or
leftward movement of the piston rod, the rod swings the rails back
to their broken line positions of FIG. 2 and swings latch element
50 to its holding condition of FIG. 9 to again positively retain
the swinging rail parts in vertical drilling positions. Cam
surfaces 55 on the latch parts 50 and 53 act to cam element 50 in a
counter clockwise direction by engagement with part 53, to enable
the latch elements to move past one another into latching
condition. The clockwise pivotal movement of element 50 relative to
its mounting bracket 50 is appropriately limited by suitable stop
shoulders, to prevent pivoting of element 50 beyond a proper
position for engagement with part 53.
The second pair of swinging rail sections 23b and 23c are also
adapted to be power actuated between vertical and inclined
positions corresponding to those illustrated in FIG. 2, and in
unison with sections 22b and 22c. For this purpose, there is
provided in conjunction with sections 23b and 23c a second piston
and cylinder mechanism 45 and related parts 49, 50 and 53 identical
with those discussed above in connection with sections 22b and 22c.
When hydraulic fluid or other pressurized fluid is supplied to the
two cylinders 45, they act to swing rail sections 22b, 22c, 23b and
23c in unison between their vertical drilling positions and their
inclined mousehole positions.
Carriage 25 to which traveling block 19 is connected includes two
frames 56 and 57 extending partially about the rails 22 and 23
respectively and rotatably carrying rollers 58 which are received
between and engage the front and rear flanges 59 of the various
rail sections in a manner effectively locating carriage 25 against
movement transversely of the longitudinal axis of the rail
structure, and guiding the carriage for movement only
longitudinally of the rails. A cross piece 156 may extend between
and rigidly interconnect the two roller carrying frames 56 and 57
of the carriage, and be pivotally connected to the traveling block
at 60 to locate the traveling block relative to the carriage while
permitting slight pivotal movement of the block relative to the
carriage.
The drilling unit 16 includes the previously mentioned rail
contacting carriage structure 24, a power unit 61 for turning the
string, and a conventional swivel 62 for delivering drilling fluid
to the string. As best seen in FIGS. 1, 4, 7 and 8, the carriage
portion of the drilling unit may include two upper and lower
parallel horizontally extending top and bottom frame members 63 and
64 interconnected by two parallel vertical frame members 65 and 66
appropriately welded or otherwise secured rigidly to elements 63
and 64. Spaced parallel vertical plates 67 project rearwardly from
member 63 and 64 at their opposite ends (FIG. 4), for reception at
opposite sides of the rails, and carry rollers 68 engaging the
front and rear flanges of the H-shaped rails, and rollers 69
engaging the rail webs (FIG. 7), to locate the drilling unit
relative to the rails and guide the drilling unit for movement only
longitudinally of the rails and parallel thereto.
The power unit 61 of the drilling assembly includes a pipe section
70 having a lower tapered external thread 71 forming a pin and
threadedly connectable to the upper end of drill string 13 to drive
it. In most instances, a conventional crossover sub 72 and a short
`pup joint` 73 are connected into the string directly beneath the
power unit. At its upper end, pipe section 70 has a tapered
internal thread 74 connectable to the rotary stem 75 of swivel 62.
This stem 75 turns with the drill string relative to the body 76 of
the swivel, which body is supported in non-rotating relation by a
bail 77 engaging hook 21 of the traveling block. Drilling fluid is
supplied to the swivel through a flexible inlet hose 78, whose
second end is connected to the derrick at an elevated location 79
well above the level of the rig floor 180.
For driving the tubular shaft 70, power unit 61 includes an
electric motor 80 having a case or housing 81 containing the field
coils of the motor and an armature 82 mounted to rotate relative to
the motor housing about an axis 83 parallel to axis 29 of the
tubular offset shaft 70. Armature 82 is journaled for rotation
within the case by a lower bearing 85, and by an upper double
thrust bearing 86 acting to prevent vertical movement of the
armature relative to the case and acting to effectively support the
weight of the armature from the case in the vertically extending
condition of the armature axis. A pinion gear 87 is connected to
the lower end of the armature shaft 88 and is engageable with a
larger diameter ring gear 89 disposed about shaft 70 and fixed
against rotation relative thereto by a key represented at 90. Gear
89 is supported against movement downwardly along shaft 70 by an
annular engagement with an upwardly facing support shoulder 91
formed on the shaft. The gears 87 and 89 may be contained within a
lower gear case or housing 92 secured by bolts 93 to a horizontal
wall 94 attached to and carried by the motor housing 81.
The driven pipe section 70 is journalled for rotation relative to
housing 81 of the motor by two axially spaced bearing assemblies 95
and 96 located essentially laterally opposite the upper and lower
ends respectively of the armature. Each of the bearing assemblies
95 includes two complementary semi-cylindrical bearing shoes 97 and
98, having complementary semi-circular radially turned flanges 99.
The inner shoe 97 of each bearing assembly 95 and 96 is received
and located within a cylindrically curving recess 100 formed by the
outer surface of a cylindrically curving wall 101 of the motor
housing. Diametrically opposite the location of this curving
housing wall, there is provided a bearing cap 102, having a recess
103 which curves semi-cylindrically to receive and locate the outer
half 98 of the bearing. Cap 102 is secured to the motor housing by
bolts 202, to locate and confine the bearings and the shaft 70
journaled therein in the relation illustrated in FIG. 5.
Appropriate means are provided for delivering lubricant to the
bearings, as for instance from a reservoir represented at 106.
A thrust bearing structure is also provided for supporting the
weight of motor 80 and its associated parts, including carriage
structure 24, from the shaft 70 which is suspended by the traveling
block. This thrust bearing is desirably located as represented at
107 in FIG. 5, vertically between an upper surface 108 of the inner
hub portion of gear 89 and the annular flange portion 99 of the
lower bearing assembly 96. Flange 99 in turn bears upwardly against
a horizontal annular undersurface 109 formed on the motor housing
to thereby support that housing. The lower race of thrust bearing
108 turns with gear 89 and shaft 70, while the upper race of the
thrust bearing as well as bearing shoes 96 and the motor housing do
not rotate.
The power unit 61 may include a brake 110 operable to apply a
controlled braking force to the armature of motor 80. This brake
may include an annular inflatable bladder 111 adapted when inflated
to force an annular braking element 112 against a cylindrical brake
drum 113 attached to the armature shaft.
It is contemplated that in some installations the housing of motor
80 may be secured rigidly to the framework of carriage 24, to
maintain the axis 84 of the driven shaft 70 permanently in a
precisely fixed position relative to the framework of the carriage.
In most instances, however, it is preferred that the motor housing
and its carried parts be mounted for slight pivotal movement
relative to the framework 63-64-65-66 of the carriage about a
horizontal axis 114 (FIGS. 7 and 8). This limited pivotal movement
of the motor may be permitted by two pivotal connections 115 and
116 at opposite sides of the motor, each including a plate 117
secured to the housing of the motor by screws or bolts 118, and a
second plate 119 secured rigidly to one of the vertical carriage
frame members 65 or 66. Pivot pins 120 are received within
registering openings in plates 117 and 119, to form the desired
pivotal connections.
Referring now to FIG. 8, it will be noted from that figure that the
center of gravity 121 of the motor and all of the parts carried
thereby is located to the right of axis 114 in FIG. 8, causing the
motor and connected parts to pivot by gravity in a clockwise
direction as viewed in FIG. 8, with that movement being limited in
the FIG. 8 position by engagement of two plates 122 attached
rigidly to the motor housing with a pair of cushioning elements 123
of rubber or other elastomeric material. These cushioning parts may
be secured to the front vertical surface of lower frame member 64
of the carriage. In the position of FIG. 8 in which cushioning
parts 123 limit the clockwise pivotal movement of the motor and
attached elements, the axis 29 of motor driven pipe section 70 is
directly parallel to the longitudinal axes of the rail sections on
which carriage 24 is located. If the carriage is in engagement with
a directly vertical portion of the track structure, the axis 29 of
driven shaft 70 of the drilling unit is directly aligned with the
vertical axis of the well (when elements 122 are in engagement with
elastomeric stop cushions 123).
Pivotal movement of the motor housing and its connected parts in a
counter clockwise direction about axis 114 as viewed in FIG. 8 is
resisted and limited by two spring assemblies 124, each of which
includes a coil spring 125 contained within a housing 126 secured
to one of the vertical frame elements 65 or 66 of carriage 24. Two
upwardly projecting lugs 127 secured to the motor housing are
engageable with pins 128 to actuate those pins leftwardly upon
counter clockwise pivotal movement of the motor about axis 114,
with the springs 125 acting through washers 129 to resist the
leftward movement of the pins and thus yieldingly urge the motor to
its FIG. 8 position in which the axis of the driven shaft is
directly parallel to the track axes.
The motor 80 is preferably air cooled, by circulation of air from a
flexible supply hose 130 (FIG. 1) through the interior of the motor
housing. Hose 130 receives air from a high capacity blower 131
connected to derrick 11 at a location spaced a substantial distance
above the rig floor 80. By virtue of this placement of the blower
and its inlet opening at such an elevated location, air is drawn
into the blower at a location well above the rig floor level at
which combustible vapors may be present, and thus the air delivered
to the motor for cooling purposes is not inflammable and can not be
ignited by the motor. For this safety purpose, it is presently
preferred that the blower be located at approximately the location
at which the hose leading to the swivel is connected to the
derrick, desirably at least about eighty feet above the rig
floor.
To now describe the operation of the drilling apparatus of FIGS. 1
through 10, the apparatus during actual drilling is in the
condition illustrated in FIG. 1, with all of the three sections
22a, 22b and 22c of guide rail 22 extending directly vertically and
in alignment with one another and with the three sections of guide
rail structure 23 also disposed vertically and in alignment with
one another. This condition of the guide rails is illustrated in
broken lines in FIG. 2. With the guide rails in that directly
vertical condition, the drilling unit 16 and its carriage 24 as
well as the traveling block 19 and its carriage 25 are all
effectively guided for only vertical movement along axis 15 of the
well, with the driven shaft 70 of the drilling unit in alignment
with that axis. Shaft 70 is connected to the upper end of the drill
string and by rotation of the motor armature is turned to
correspondingly turn the drill string and perform a drilling
operation. During that drilling operation, a pair of links 132 may
be suspended by the side portions 133 of hook 21, but be deflected
by the swivel to an inactive position between the rails as
represented in FIG. 2. An elevator 134 may be suspended by the
lower ends of these links 132 for use in hoisting the drill pipe
when the drilling unit is in its inactive position.
As the drilling progresses, the drilling unit and string gradually
move downwardly, ultimately to the full line position of FIG. 1,
beyond which further downward movement of carriage 24 and the
drilling unit is prevented by engagement of the lower rollers 68 of
the drilling unit with the bottom stop plates 41 of the rails (see
FIGS. 7 and 8). With the drilling unit in this position, slips are
placed in a master bushing assembly 135 in the rig floor (or in a
rotary table 136 located in the rig floor) and about the upper
section of the drill string, to support the string independently of
the drilling unit, following which the pup joint 73 is rotated by
motor 80 to detach the pup joint from the remainder of the string.
The draw works is then actuated to raise the traveling block and
connected parts upwardly a short distance, as for instance to about
the level illustrated in FIG. 2, and the piston and cylinder
mechanisms 45 are then actuated to swing the lower sections 22b,
22c, 23b and 23c of the rails rightwardly to the full line inclined
positions of FIG. 2 in which shaft 70 of the drilling unit and pup
joint 73 are aligned with a length of pipe 137 in mousehole 30. The
traveling block and connected parts are lowered sufficiently to
bring the pup joint 73 into engagement with the stand in the
mousehole, and the motor of the drilling unit is then turned in a
make-up direction to connect the pup joint to the stand in the
mousehole. The connection may be completed by tongs or other
equipment, and the traveling block is then actuated to lift the
drilling unit and connected stand upwardly along the inclined
tracks 22b, 22c, 23b and 23c. In some instances the length of the
stand within the mousehole will be greater than the combined length
of the lower two sections of each track assembly. For example, the
height of pivotal connections 28 may be sixty feet above the rig
floor, while the length of a triple stand in the mousehole may be
ninety feet. Consequently, when the drilling unit reaches the
location of the upper ends of the inclined portions of the tracks,
there may still be a portion of the stand contained within the
mousehole. As the drilling unit and its carriage move upwardly
beyond the location of the pivotal connections 28, they move onto
and are directed exactly vertically along the upper fixed portions
22a and 23 a of the sectionally formed rail assemblies. Since the
stand being moved from the mousehole is still at a slight angle of
inclination at this time, the entire motor 80 pivots slightly in a
counterclockwise direction as viewed in FIGS. 2 and 8 relative to
the directly vertically extending carriage 24, and as permitted by
the pivotal connections 115 and 116 represented in FIG. 7. This
pivotal movement of the motor and driven shaft 70 about axis 114
relative to carriage 24 is resisted by spring units 124 of FIG. 8,
and as a result the motor pivots only the amount necessary for
effective removal of the stand from the mousehole. When the stand
is completely withdrawn from the mousehole, springs 125 and the
weight of the stand return the motor and stand to a directly
vertically extending condition of alignment with the well axis, for
connection to the upper end of the string by rotation of the motor
and tightening tongs, after which the slips which had been
suspending the drill string from the rig floor may be removed and
the drilling operation may be continued. At an appropriate time
during withdrawal of the stand from the mousehole, as for instance
after the carriages of both the drilling unit and traveling block
have reached positions of engagement with the upper stationary
portions 22a and 23a of the rails, power cylinders 45 may be
actuated to return the inclined portions of the tracks from their
full line position of FIG. 2 to their broken line drilling position
of that figure, to be latched in those vertical positions by
latching parts 50 and 53 as previously discussed.
If it becomes desirable to move a length of pipe from the upper end
of the string to the mousehole, this can be accomplished by a
reversal of the above discussed procedure, that is, by first using
tongs or other equipment to break the connection between an upper
section of the drill pipe and the remainder of the string, then
actuating motor 80 to spin the upper section out of the string,
then swinging the rails to the inclined full line position of FIG.
2 to move the detached section into alignment with the mousehole,
and then lowering the section into the mousehole and energizing
motor 80 to unscrew the drilling unit from that section.
When it is desired to remove the string of pipe or a portion
thereof from the well, and/or to lower a portion or all of the
string of pipe back into the well, the present apparatus permits
performance of that function by conventional tripping equipment
without interference by the drilling unit and related equipment of
the invention. To convert the apparatus to this tripping mode, the
carriages 24 and 25 are first pulled upwardly by the draw works and
traveling block, with the rail sections all in their directly
vertical drilling condition, to positions in which the lower
carriage 24 is just above the lowermost rail sections 22c and 23c.
With both of the carriages thus out of engagement with the lower
rail sections, section 22c is swung pivotally about its axis 33
from the active full line position of FIG. 4 to the retracted
inactive broken line position of that figure. The traveling block
and connected parts may then be lowered to move carriage 24
downwardly into engagement with rail section 23c, but not in
engagement with rail section 22c by virtue of the discussed
positioning of section 22c in its inactive condition. When all of
the rollers of carriage 24 are properly in engagement with bottom
rail section 23c, and the carriage is supported on the bottom wall
41 of that rail section, gate 121 of hook 21 is opened, and the
entire drilling unit and swivel assembly and the connected rail
section 23c are swung pivotally about vertical axis 34 from the
full line position of FIG. 4 to the broken line position of that
figure. During such movement, the bail 77 of the swivel moves out
of its position of connection with hook 21. In the retracted broken
line position of FIG. 4, the entire drilling assembly and all of
its connected parts are well away from the vertical axis 15 of the
well, and offer no obstruction to hoisting and lowering of the
drill string by the traveling block and hook 21. As the swivel
moves away from the hook, links 132 and elevator 134 swing
downwardly to vertical positions as represented in FIG. 3, in which
the elevator may be brought into contact with a section of the
drill string, to hoist it upwardly to a position in which a next
successive section can be supported in the slips and the upper
section can be detached from the string in conventional manner. The
entire string may be removed sectionally from the well in this way,
and then placed back into the well by a reverse operation, to
complete a round trip of the string in minimum time without
interference by the drilling unit and without causing wear on the
motor or other parts of the drilling unit such as would occur if
the drilling unit itself were utilized to trip the pipe.
After completion of the round trip, the drilling unit including the
motor, swivel, etc. can be swung back to the full line position of
FIG. 4 (with track section 22c still in its inactive position) the
bail of the swivel can be connected to hook 21, and the traveling
block can be utilized to raise both carriages upwardly far enough
to permit bottom rail section 22c to be swung back to its active
position thus placing the entire apparatus in its original drilling
condition.
FIG. 11 illustrates fragmentarily a quick disconnect shaft
arrangement which may be utilized in lieu of the integral one piece
shaft 70 of FIG. 5. In FIG. 11, the two main motor bearings 95a and
96a may be identical with bearings 95 and 96 of FIG. 5, and may
have the same relationship to the rest of the motor, gears, etc. as
illustrated in FIG. 5. Instead of the unitary one piece driven
shaft 70 of FIG. 5, the FIG. 10 arrangement includes a tubular part
70a, having a straight cylindrical inner surface 138 and an upper
internally non-circular and preferably hexagonal recess 139. A
tubular part 140 is removably receivable within element 70a, and
has an externally non-circular portion 141 engaging non-circular
recess 139 in driving relation. The second part 140 has an upper
tapered internal thread 141' and a lower tapered externally
threaded pin portion 142, with this pin portion being threadedly
engageable with a short attaching tube or pipe 143 in the
illustrated relation to clamp part 70a between shoulders 144 and
145 on parts 140 and 143 to integrate the parts 70a, 140 and 143
into a unitary structure driven rotatably by the motor. The lower
threads 146 of part 143 are then connectable to the drill string in
the same manner as the lower threads of part 70 of the first form
of the invention, to drive the string rotatively. Gear 89 drives
part 70a in the same manner discussed in connection with gear 89
and part 70 of the first form of the invention.
If it becomes desirable to remove and replace the threaded portions
of the shaft assembly of FIG. 11, this may be done quickly and
easily by merely breaking the threaded connection at 142 between
parts 140 and 143, and then withdrawing the part 140 upwardly from
within pipe 70a. Replacement parts may then be connected to tube
70a to return the apparatus to operative condition without removal
of the main driven shaft part 70a of the motor assembly.
While certain specific embodiments of the present invention have
been disclosed as typical, the invention is of course not limited
to these particular forms, but rather is applicable broadly to all
such variations as fall with in the scope of the appended
claims.
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